ESA  DOR cross support

1. ESA DOR cross support Mattia Mercolino, ESA/ESOC CCSDS Fall Meeting 2007

2. Summary • ESA DOR technique has been validated with VEX (2006) and Rosetta (2007) operational campaigns • The system is now mature to be used for cross-cooperation with other Agencies • With JAXA, to enlarge existing Japanese baselines and to provide a Japan-NNO N-S baseline • With JPL, since NNO-CEB baseline is almost perpendicular (and therefore complementary for orbit determination) to the Goldstone – Canberra baseline • ESA and JPL have already started the definition of a roadmap for cross-support / interoperability • First chance to experiment DOR cross support could be on JPL mission to Mars Phoenix CCSDS Fall Meeting 2007

3. Data translators (1) • To start any kind of interoperability without impact on the existing hardware, ESA started building raw data translators from ESA raw data format to the format used by JPL or JAXA correlator (and vice-versa)  Need for a S/W data translator • Translators are unavoidable, due to the difference in data format and data contents (i.e. different sample rates used by the two agencies) coming from the different hardware implementation • No need for a standardised S/W translator algorithm • Need for exchange of ICDs and of raw data sample CCSDS Fall Meeting 2007

4. Data translators (2) • ESA has developed and is currently validating a S/W data translator both from/to JPL-VSR and VLBI-MKV formats CCSDS Fall Meeting 2007

5. ESA DOR support to JPL • First ESA possible DOR support to JPL is with Phoenix • Phoenix has extremely stringent navigation requirement (requirement for JPL DOR is of 60 ps accuracy) • It is equipped with a transponder capable to generate DOR tones at ±19MHz at X-band only • ESA cannot use the same BW JPL is using. Limitation to 28MHz BW • The use of this BW would anyway guarantee accuracies down to 0.22 ns with quasars having flux of 0.7 Jy • A plan to demonstrate the feasibility of ESA support to Phoenix has been agreed together with JPL CCSDS Fall Meeting 2007

6. Roadmap for DOR support (1) • Currently, the interoperability has been tested in only one direction (ESA spacecraft tracked by JPL antennas and correlation results provided to ESA OD team by JPL) • Possible scenarios for progressive steps of interoperability validation are: • “calibration step”: ESA planetary orbiting S/C simultaneously tracked by 2 ESA and 2 JPL antennas. Independent correlation processes performed by JPL and ESA. Final DDOR results validation by ESA OD team • ESA S/C tracked by one JPL antenna and one ESA antenna. Exchange of raw data and correlation performed at both ESA and JPL. DDOR data analysis by ESA OD team • JPL S/C tracked by two ESA antennas, correlation results and OD provided by ESA to JPL • JPL S/C tracked by one JPL antenna and one ESA antenna. Exchange of raw data and correlation performed at both JPL and ESA. DDOR data analysis by JPL OD team • JPL S/C tracked by two ESA antennas, correlation results and OD provided by ESA to JPL CCSDS Fall Meeting 2007

7. Robledo Goldstone Cebreros New Norcia Roadmap for DOR support (2) • Step 1 (“calibration step”) already performed on VEX and Rosetta during the DOR operational support. A doc will be produced in which results are described. • Step 2 would need an ESA orbiting S/C (for which already exist an agreement between the two Agencies) VEX to be tracked in the following scheme • The tracking should be structured as follows: • Simultaneous tracking from CEB-NNO and Robledo • Simultaneous tracking from Goldstone-Robledo and CEB • This step would validate ESA data translator and correlator with the one of JPL CCSDS Fall Meeting 2007

8. Roadmap for DOR support (3) • Phoenix launch was in August, the concept validation has been started before • VEX was chosen as the probe to be tracked, since it is an orbiting S/C (whose position is already well know by means of standard radiometric tracking techniques) • Two sets of tracking test passes were performed: • First test in July • Second test currently being done • Final results (validation by ESA flight dynamics) are expected by the end of October when the processing of all data is completed CCSDS Fall Meeting 2007

9. 6 months 1 year 1 ½ year 2 years June 2006 Translator Step 1 Step 2 Step 3 Step 4 Step 5 Roadmap for DOR support (4) • After the cross-validation with VEX, the step 3 could be undertaken. This would mean to track a JPL S/C with the same scheme used for VEX. The S/C could be, at that point, directly Phoenix • The schedule for completion of the overall interoperability / cross-support concept is given below CCSDS Fall Meeting 2007

10. Possible ESA DOR support to JAXA • JAXA currently uses K5 raw data format • This is a VLBI compatible data format (very similar to Mk-V format) • The translator under development is able to treat the Mk-V format • An agreement for the formalisation of cooperation on delta-DOR has been reached in January 2007 • Definition of interfaces on going • Future steps: • Definition of level of cooperation • Identification of suitable missions, for cooperation demonstration • Preparation of a suitable test campaign CCSDS Fall Meeting 2007